Identification system



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IDENTIFICATION SYSTEM Filed July 2, 1959 8 Sheets-Sheet 7 FROM MEMORYRESET (AFTER READ-OUT) FROM RECORD ONE TO ALL MEMORY ELEMENTS Y r J FROM:"1" X x DIGIT COUNTER V v TO ALL MEMORY IF 0 X ELEMENTS OF ONE FROMIMPERFEGT DIGIT DIGIT SYMBOL r Re 5 9 FF T0 READ-OUT lloll COUN- TERIMPERFECT DIGIT RECORDER RECORD SYMBOL FOR IMPERFEOT DIGIT RECORD "ONELAST BIT 8 1964 H. B. BRAINERD 3,145,291

IDENTIFICATION SYSTEM Filed July 2, 1959 8 Sheets-Sheet 8 64 64 l 68' ll 68 202 l Ml flrzz'rzmd United States Patent 3,145,291 IDENTIFICATIONSYSTEIVI Henry Bowen llrainerd, Upland Road, Weilesley 81, Mass.

Filed Italy 2, 1959, Ser. No. 824,542 12 Claims. (Cl. 235-6111) Thisinvention relates generally to an identification system and is moreparticularly concerned with a fully automatic identification system formoving vehicles such as railroad vehicles.

It is not an exaggeration to state that in considerable measure theprosperity of our nation depends upon the health and prosperity of therailroads, the backbone of our transportation system. No more effectivescheme has been devised to transport large numbers of people and goodsfrom one point to another safely, economically and comfortably. Whilethe role of the railroads has changed with the improved technology ofthe automobile and aircraft industries there is no doubt that therailroad system is a vitally necessary part of our transportationnetwork.

Yet history has frustrated the capabilities of American railroads infinding their proper role in respect to the other forms oftransportation. The regulatory practices of the Interstate CommerceCommission and the Public Utility Commissions of various states, therailroad brotherhoods and in part the railroad managements themselveshave contributed to the problem. Handicapped partly by tradition, byunion restrictions and by a maze of reguiations to which no otherprivate sector of the economy is subject, the railroads for many decadeshave sought to deal efiiciently with the day-to-day handling of freightand passengers within the statutory rate framework permitted them. As aresult, for these many decades there has been continuing analysis of theeconomics of railroad operations. This in turn has brought forth amultitude of proposed solutions and inventions designed to decrease costand increase efficiency and safety in the handling of railroad vehicles.Yet in many phases of railroading the number of man hours required todeal with matters substantially routine and repetitive have not beensatisfactorily reduced.

New schemes are constantly being introduced to facilitate theassignments presented to the railroads in each days operations. Butthese improvements, heretofore, have been generally no more than thestreamlining and refining of the efforts of men and use of manpower.

The problem of identifying and assorting freight cars is one of themajor tasks of practically every railroad. It is a function performed ina classification yard and is comparable to the function of a sorter in apost oifice who places letters into various mail sacks according totheir destination. A classification yard is the center at which arrivingfreight rtains are broken up and the cars sorted according todestination to form new trains.

Cars are loaded at private sidings or public freight depots. A documentcalled a waybill is made out for each car giving the car number, route,destination, consignee, shipper, contents, special instructions, and anyother pertinent information. This waybill accompanies the car fromorigin to destination of the shipment in the charge of the conductor ofthe train in which it is hauled.

Loaded cars in metropolitan areas are taken by a switcher to assemblyyards. At outlying points cars are picked up by a way freight. Cars gomost of the distance in through trains, and are eventually set out atdestination by a way freight or switcher. Usually, except for a fewshort hauls, a car goes through one or more classification yards.

In most cases, the cars are brought to a freight yard 3,145,291 PatentedAug. 18, 1964 in the order in which they were picked up and are notsorted for their destination. Up to the early 1900s all classificationwas done in flat years, where a switch engine shuttled back and forthhauling cars out of one track and shoving them onto another. The yardconductor referred to his handful of waybills, while his crew threwswitches, coupled and uncoupled cars, released and set brakes inresponse to his hand signals. This is still done to some extent.

About the beginning of World War I, hump yards were introduced. While alocomotive pushed cars slowly over the hump a rider got on each car tohandle the brakes, a man uncoupled each car and the yard conductorsignaled track numbers to a crew of switchmen who threw the switches byhand.

Somewhere about this time it became common practice to walk down a trainand write down car numbers in order, then fill in track numbers from thewaybill information to form a switch list. This was much more convenientfor switching and protected the waybills from rough handling.

In the 1920s the car retarder was introduced. This is a power operateddevice along the track which presses on car wheels by manual control andslows the car down, eliminating the need for riders. Along with thismechanization the yard switches were made power operated. This allowedthree or four men to handle the retarders and switches for an entireyard. Each man received a duplicate copy of the switch list, either bypneumatic tube or by Teletype.

In the 1940s the control of the retarders was automated with anelectronic analog computer, which could take into account the weight androllability of each car, the curve resistance to the selected track, thenumber of cars in the selected track and wind velocity, so

that each car would leave the last retarder at a speed that would let itcouple onto the car ahead without damage. Switch controls were arrangedfor pre-programming, and in some cases the teletyped track number cancontrol the switches without any action by the operator. With thissystem one man can supervise the retarders and switches of the largestyard.

During this same period there was a trend toward fewer and biggerclassification yards made possible in part by the increased use ofsemi-automatic techniques. Today, cars out of New York and Boston, forexample, may be classified at Selkirk for as many as forty destinations.Several destinations will form blocks in a train; each block can be setout in a simple switching operation instead of reclassifying the entiretrain. This saves both car time and operating costs. A car from Chicagoto Boston which might have stopped eight or ten times forclassification, with a delay of a day or more at each yard during theera of fiat switching, can now travel the same distance with only two orthree stops, each stop requiring only half a day or less.

At the present time, the clerical work of recording the car numbers,checking against waybills, and preparing switch lists has emerged as amajor item of labor costs and delay in the classification, switching androuting of cars. Costs and delays have been somewhat reduced by usingclosed circuit television techniques. A TV camera at the entrance of areceiving yard scans incoming trains and a clerk in the yard ofiicereads the car numbers from the TV monitor screen into a tape recorder.

When a train pulls into a receiving yard the conductor sends theaccompanying waybills to a clerk who arranges them in order with the carnumbers as tape recorded and prepares the switch list from thisinformation. This list may be typewritten then carried by pneumatictube, transmitted by Teletype, punched in tape for later Teletypetransmission, or punched in IBM type cards.

Modern communications techniques such as two-way radios, pagingloudspeakers, and two-way loudspeakers, direct switch engines movingblocks of cars to the departure yard, men connecting air brake hoses,and other necessary operations.

While much of the hard and dangerous physical labor of theclassification process has been reduced there is still need forpersonnel to observe, record, verify, and supervise the various sortingoperations. What has been required, therefore, is a means ofautomatically identifying individual railway cars, storing theinformation, sorting the information, and then matching the identitiesof the cars to their destinations in order to assemble cars in groups bydestination.

It is an object of my invention accordingly to provide completelyautomatic means for the identification of railroad cars.

Another object of the invention is to provide fully automatic recordingand storage means for the identity data. A further object of theinvention is to provide a completely automatic identification systemwhich can economically be used by all railroads and freight cars in thecountry. An additional object of the invention is to provide anautomatic system of identification having an inherent high order ofreliability.

A further object of the invention is to provide identification meanswhich may be visually inspected and which moreover correspond characterby character to the identifying lettering of the car.

Still another object of the invention is to provide an identificationsystem which can be used at interchanges with other railroads toautomate car accounting with considerable reduction in clerical laborand errors, and with fewer delays of cars. A still further object of theinvention is to provide a system of identification which can besuccessfully integrated with current communication facilities such asrailroad Teletype equipment and associated devices. A still furtherobject of the invention is to provide an identification system which canbe used with currently available digital computer equipment with littleor no modification. Still another object of the invention is to provideautomatic identification to give an up to the minute report on thelocation of any carload shipment at negligible cost. Another object ofthe invention is to provide a system which can be used with a hot boxdetector to identify a bad-order car. A further object of the inventionis to provide an identification means for each car which is passive,requiring no further energy sources, and which requires m nimal upkeepand infrequent replacement. An addition object of the invention is toprovide an identification scheme which in large measure employscomponents and techniques which have been thoroughly tested and haveknown operational reliability, operating tolerances, and limitations.Still another object of the invention is to provide an identificationsystem having a primary unit capable of withstanding the rigors ofcontinuous exposure to the weather and to the environment andcircumstances in which railroad operations generally occur. Anadditional object of the invention is to provide identification meanswhich operate entirely independently of the structural material of thecar. Another object of the invention is to provide identification meanswhich do not project beyond the existing structure of the car. A furtherobject of the invention is to provide an identification system which isdesigned to work satisfactorily over any range of car widths and floorheights now in use or known to be proposed. A still further object ofthe invention is to provide a system which meets the highest standardsof safety. Another object of the invention is to provide anidentification system which avoids the use of radio signals and thuswill not interfere with other forms of communication.

In the accomplishment of these and other objects of my invention therailway cars or other vehicles to be identifled are provided withradiant energy lCLSCllV markings.

A radiant energy source directs light in this embodiment upon themarkings. In the description which follows the directed energy has beensometimes termed interrogating energy. A sensing device is positioned inoperative relation with the vehicles so that reflections from themarkings, which will be coded for each vehicle, can be sensed thereby.

A feature of the invention is the use of light energy retro-reflectivematerials for the coded reflective markings. Retro-reflective materialis material which reflects light back close to the same axis as theinitiating or incident energy. Retro-reflective light energy is not onlypositionally or geometrically more easily sensed than specularlyreflected light but its concentration also permits better discriminationof the information carrying reflections from ambients in theenvironment.

Thus the wayside device has one unit which directs a beam of radiantenergy on the reflective markings and a second unit, a sensing device,which picks up the coded reflected energy therefrom.

Another feature of this invention is that the coded markings cancomprise a series of blocks of grouped vertical strips ofretro-refiective material with spaces between. The strips are threedifferent colors, for example, red and green positioned on a whitebackground so that a white strip separates the colored strips. The totalnumber of strips is fixed and an identifying binary code is formed byvarious patterned combinations of the two colors on white. For example,a red strip could represent zero and a green strip could represent onein a binary code system. Each patterned block of six colored strips withWhite strips between represents a single alpha-numeric character. Thenblocks total, representing ten characters, would be adequate to identifyevery railroad car in North America allowing four digits for the ownersdesignation and six digits for the owners number for the particular car.A further feature of this scheme is the basic simplicity and economy or"using reflective sheeting for an energy interrogatable coded system foreach railway car. The fact that the markings are passive is anotherfeature of the system.

There is already available retro-reflective material having minute glassbeads imbedded in a suitable binder on adhesive sheeting. The code canbe preprinted of red and green strips on white sheeting leaving whiteareas between the strips or separate colored strips may be pasted insuitable patterns. If each block of sheeting represents one character ordigit, the white between, responding on both red and green outputs ofthe radiating sensing system would advance a counter or sequencer forcode elements of one character, while the non-reflecting or blacksurface of the car between characters would count the characters. Makingeach digit block a separate piece allows assembling any required vehiclemarking from standard pieces, and permits placing the pieces in whateverspaces are left by rivet heads, ribs or other protuberances.

The wayside device includes a radiant energy source having an opticalsystem to limit the horizontal width of the radiated energy. Sensingmeans responsive to the coded reflective energy consists basically ofphotocells placed close to the same axis as the source or" light energybut properly screened therefrom.

The sensing device is coupled to a recording device which can be locatedremotely. It will include as many recording elements as there are stripssensed on a car. plus a sequence connecting device. The non-reflectivespaces between the strips cause a greatly decreased output from thelight responsive circuitry which is arranged in turn to cause thesequence connecting device to advance to the next series of recordingelements.

A further feature of the invention is the use of conventional datacompilation and storage techniques for the received coded pulsesreflected from any particular car. These techniques are versatile,mature, well-advanced and well-known. The sequence connecting devicecould be rotary stepping switches or counting chain of relays, or vacuumtubes or transistors. The recording elements could be relays, vacuumtube flipfiops, transistor flip-flops, magnetic cores, or any otherconvenient digital device. These are arranged to transfer the record ofeach car to some punched or magnetic medium with enough capacity torecord one or more trains. This medium may be remote from the sensingdevice.

The use of an optical system is another feature of the invention and ispreferable to any other system such as magnetic, or electro-magneticinterrogation techniques because of the wide variety of materials usedin cars, for example, steel, stainless steel, aluminum, and Wood.Moreover, using radio energy can cause interference problems.

Still another feature of the invention is that the use of a light sourceand retro-reflective coded markings and a reflected light sensing deviceallows a large tolerance both in vertical, lateral, and longitudinallocation of the markings to fit the construction of the different carsand in the location of the sensing device relative to the track. Anadditional feature of the invention is that the method of sensing isindependent of the speed of the cars past the sensing device. A furtherfeature of the invention is that the use of a fixed number of elementsin the identification code strip, each of which must be sensed as eitherone of two colors, provides inherent self-checking. An additionalfeature of the invention is that self-checking can be provided ifnecessary. Yet another of the features of the invention is that theretro-reflective material will provide an additional safety feature,particularly at highly crossings at night. Another feature of theinvention is the provision of a standard numeral or letter on the binarycharacter and digit blocks to permit visual as well as automaticidentification. This also insures correct placement on the vehicle side.

Application of the retro-reflective material to cars is an extremelysimple and inexpensive operation. Thus it is another feature of theinvention that the application by means of a stencil or fully preparedadhesive sheets insures that the labor cost per car is of the order ofmagnitude of one or two dollars at the most. Because each block has anumeral or letter thereon equivalent to its binary form, visualselection is greatly facilitated and installation can be performed byunskilled labor. Moreover, periodic inspection requires nothing morethan a man who can read and use a flashlight.

Another feature of the invention is that all the components necessaryfor the sensing device are currently available. Design criteria arewell-known and component reliability under the most unfavorableconditions has been thoroughly demonstrated. Still another feature ofthe invention is the applicability of the resulting coded information inthe form of electrical pulses to current Teletype relay techniqueswhether the standard Teletype code of five units is employed or the IBMsix-unit code.

These and other features of the invention will best be understood withthe aid of the accompanying drawings in which:

FIG. 1 is a perspective view of railway cars and an engine bearing codedidentification strips with a wayside device mounted in operativerelation to the strips;

FIG. 2 is a block diagram of the identification system;

FIG. 3 shows the arrangement of the coded markings aflixed to eachrailway car;

FIG. 4 is a diagrammatic representation of the optical system of thewayside device taken on a horizontal s ction;

FIG. 5 is a top view in schematic form of the operational relationshipbetween the wayside device and the vehicle markings with the energyradiation and reflective pattern indicated. Maximum and minimum carwidths are also shown;

FIG. 6 is a view of the wayside device in operational relationship withthe coded vehicle markings viewed along the vehicle axis. Maximum andminimum car widths and maximum and minimum car heights are alsoindicated;

FIG. 7 is a general schematic arrangement of the signal inputs to thestorage system showing logic, bit counterrecorder, digit counters,read-out converters, and matrix of memory elements;

FIG. 8 is a block schematic arrangement of the initial portion of a bitcounter and associated logic;

FIG. 9 is a block schematic of a typical element in a memory device;

FIG. 10 shows a block schematic of the final portion of a bit recorder;

FIG. 11 is a diagrammatic representation of an alternative light source.

(i) Equipment Generally The preferred embodiment of my invention hereindescribed is shown in blocks in FIG. 2 and comprises the combination ofbinary coded retro-reflective markings 2t) afiixed to each of thevehicles to be identified, and a wayside device 22 mounted near thetrack side to function in operational relationship with the codedmarkings 29. The Wayside device 22 consists of two separate units, aninterrogating unit 24 which shines or directs a vertical, narrow beam ofradiant energy (light) upon the markings 20 and a sensing unit 26 whichis responsive to the energy reflected from the markings. From thesensing unit 26 electrical signals corresponding to the code pattern ofreflected energy are fed to appropriate computer logic 28 the output ofwhich is in turn fed to a computer storage unit 3% or local memory 32,and there to various read-out devices 34 and 36. For remotely locatedequipment, a transmission facility 33 is made part of the system.

(H) Operation Generally Each railway vehicle 40 has aflixed to its sidean identification code made up of ten patterned blocks 42 ofretro-reflective material. Each such block 42 consists ofretro-reflective strips 44 of two colors alternating with a strip ofwhite reflective materiai between the colors. The Wayside device 22 ispositioned in respect to the track side so that light energy from theinterrogating unit 2a is directed at the reflective blocks 42 which arearranged in an identification code. The sensing unit 26 is positioned toselectively respond to the three values of reflected light energy, twodifiierent colors and white, caused by light emitted from interrogatingunit 24 being reflected from the strips 44 which make up the blocks 42.The sensing unit 26 distinguishes each of the two colors and white,changing the reflected energy into corresponding electrical pulses. Thepattern for each block 42 is made of the two colors with White betweenand represents in digital or binary notation a particular letter ornumber character. The computer iogic assembles the electrical pulses,each of which corresponds to a binary digit (bit), into a collection ofsix bits forming a letter or number character and then collect the tencharacters which form the coded designation of the particular vehicle.The designation is fed to the storage unit 30 and/ or local memorydevice 32 to be retained at least long enough for any single train ofcars 46 to pass. The information stored can either be permanentlyrecorded on IBM cards or tape, transmitted to a remote location, printedin alpha-numeric form or temporarily presented, for example, on alighted board. Alternatively, the logic-recording system 28 and 30 mightbe arranged and programmed so that cars of any particular codedesignation having been interrogated and sensed would initiate a seriesof directions addressed to some other computer program.

(III) Coded Markings As shown in FIG. 1 each car 40 would have afiixedto the sides thereof ten blocks 42 of the coded markings 2t).

An individual block 42. is shown in FIG. 3. Each block is about 2 x 5",and is composed of six colored strips 44 of retrorcilective material,with what is in effect a white strip between each colored strip forminga pattern which can be arranged in sixty-four permutations. The patternscan be fabricated by printing the particular color pattern thereon ormight be fabricated more conveniently by using a sheet of whiterctrorellective material on which the color strips 44 are applied.

The code pattern on each block 42 is made digital by having one of thecolored strips 4% represent bi ary zero, the strip of the other colorrepresenting binary one. Each of the ten blocks 42 can thereby representin digital form an alphabetical or numerical character. Thus, in thesimplest binary notation, a block 42 having. for example, red and greenstrips with green representing one and red zeroj a left to r'nht p ern(ignoring the white strips in between) of red een-ttdqed-re l-redwouldindicate the number two and a pattern of stripsrcd-green-grcen-red-rct;l-rctlwould correspond in binary form to thenumber 6 as sh in FIG. 3. A combination of ten blocks 42 are sufficientto give an identification designation for all the aiiroad cars in NorthAmerica using four blocks for the owners alphabetic code and theremaining six for the numerals.

While the colors green and red have been chose purposes of thispreferred embodiment it should be pointed out that the articular colorsare unimportant so long as they are 5.. Mcntly different. The two colorschosen should be selected to be spectrally qt 'te dist'nct anddistinguishable. There is no reason. o course. why the two dillercntstrips could not be dis .guishable by video sensing means and yetundillerentiatable by the human eye. Also. different strips havingdifferent polar ing characteristics could be employed. it would seem tobe an advantage to use visually disti colors thus permit readynon-automatic obsei on the correct blocks are properly arranged. Anadditional element convenience is providing each code bl cl: 4?. withthe equivalent actual number or letter printed thereon. A furtheradvantage of visible red and green St ips is that the markings wouldserve as an added safety measure.

For the markings the material Scotchlite is available. It is a flexiblesheeting with retro-reflective glass beads on the face andpressure-sensitive adhesive on the back, obtainable in white and colors.Transparent inks are available for printing or stenciling. It is moreeasily applied and is presently more efficient optically than anyavailable retro-reflective paint.

for

(IV) Wayside Device The wayside device 22 consists of .vo closelysituated but distinct units, the inerrogating unit 24, and the sensingunit 26. The interrogating unit 24 is basically a light source whichdirects at the sides of passing railroad vehiclcs 4G a horizontallynarrow band of radiant light energy 4@ having a considerable angulardimension in the vertical plane. As each railroad car 46* moves past theband of light energy it, the various coded data patterns of green. whiteand red strips on the blocks 4-2 affixed to the sides of the cars willreflect light of different color values to which the sensing unit 2-6will respond.

The light source 24 concentrates its output on an area a foot high andless than half an inch wide at a distance of 3'0" to 3'6" from theprojector. The sensing unit 26 must pick up the retro-reflected light asclose as possible to the source projector and separates red and greencomponents onto two light responsive means. The light projected onto themark'ngs 2d must be bright enough that the retro-reflected componentreaching the sensing unit 26 is markedly stronger than the brightestdiffused reflection of sunlight or any other ambient light. Powerlimitations at a remote location and signal-to-noise ratio in the sensedinformation require that optical elficiency be maximized.

(A) interrogating Unit In FIG. 4 there is shown in horizontal section adetail of radiant energy source or interrogating unit 24. A light source43 which is a point or vertical line of light is located near the rearfocus of a substantially elliptical reflector section 52 in such a wayas to concentrate light at a focal point 54 some distance from thefocus. The reflector $2 could also have a semi-cylindrical shape, or anyconfiguration capable of focusing a vert cal line of light. In front ofthe focal point 54 is a combined transmitting lens and prism 56 forprojecting the light in a beam essentially parallel in horizontal crosssection; the focus 54 of this lens and prism 56 is also the front focus54 of the elliptical reflector 52.

(B) Sensing Unit The narrow vertical band of light 46 played on thecoded blocks 42 causes light of various spectra to be reflected back tothe sensing unit 26. The latter is located roughly on a common verticalaxis with the interrogating light source unit 24-. Since the reflectionsare parallel to the initiating stimuli, a receiving lens 58 similar tothe transmitting lens 56 focuses the retro-reflected energy. A verticalslit 6G is provided near the focus 62 of the receiving lens 58 to limitaccepted light to a region narrower than the image of any given strip44. Immediately behind the slit 6% and located at a diagonal thereto isa dichroic mirror 64. A dichroic mirror is one which will transmit onecolor but will reflect another. A light sensing device 66 for thetransmitted color is located behind the dichroic mirror and a lightsensing device 68 for the reflected color is located at an anglethereto.

Indicated diagrammatically in FIGS. 5 and 6 is the operation of theinterrogating beam of light 46 upon the coded markings i2 and the effectof various car widths and floor heights. Thus in PEG. 5, thehorizontally narrow light beam 46 represented by parallel double lineswith arrows is directed at car sides of a maximum width car 72 andminimum width car 74. Retro-reflected energy 70 represented by twoparallel solid lines with arrows in the opposite direction is returnedto the sensing unit 26 along the same axis as the interrogating beam 46.Light reflected specularly from the markings is represented by thedashed lines 76. A shield 78 is provided to prevent interfering lightfrom being reflected specularly to the sensing device.

A side view of the interrogating light beam 46 in FIG. 6 indicates themanner in which the vertically spreading light energy can accommodatemarkings on the widest car 72 with a considerable difference between thelowest and highest car floors where the blocks 20 can be afhxed. FIG. 6also shows a narrow car 74 with low 8% and high doors. The verticallywide angular configuration of the light beam 46 thus permitsinterrogation irrespective of either the floor height or of the width ofany vehicle 46.

(C) Logic It should be noted that the logical units shown here are notnece rily the simplest that will accomplish the purpose, nor 18 theoperating sequence necessarily the only one. The units and sequence heredescribed demonstrate, however, the practicability of the whole system.In fact, there are many devices already available commercially whichwith only a slight amount of modification could perform the sequencesoutlined below or at least give the same described result.

As the cars move past the light beam 46, the various strips 44 on any cawill reflect light of different color or spectral values, green, red andwhite. The light sensitive devices 66 and 68 either separately orsimultaneously (in the case of white reflected light) convert thereflected energy into electrical pulses. The absence of re llccted lightalso has operative significance and thus can be considered as a fourthelectrical input pulse.

The general operation of the sensing logic can be explained withparticular reference to the block diagram shown in FIG. 7. The twosensing inputs R and G stand for red and green and are equivalentrespectively to and 1 corresponding to the different energy valuesrefiected from the identification code. The logic elements in block 84determine whether one signal is present or both or neither. The fourpossible inputs consist of red presentgreen absent (115), redabsent-green present (FG), red and green both present (RG), or neither(It G) all of which are fed into a bit counter-recorder 86. When (TlG)occurs one is recorded, when (Rf?) occurs zero is recorded. When bothred and green are present (RG) the bit counter 86 is advanced and whenneither red or green is present (FE) the counter is reset.

The six leads, 88, 9h, 92, 94, 96, and 98, from the bit counter-recorder85 represent as many successive output paths as there are bits in adigit or character, in this case six bits. After the first bit isrecorded through the first output, an advance bit counter signal causedby reflection from a white strip will transfer it to the second output,then to the third, fourth, fifth and sixth, as each bit is recorded. Butbefore the first bit is recorded, the advance bit counter signal willhave no effect. A reset signal before the last bit is recorded willcause the imperfect digit code to be substituted for whatever has beenrecorded.

A digit counter 10th will have as many outputs 1192- 129 as there aredigits. The schematic intersection of an output from the digit counterlltltl and one from the bit counter 86 is the location at which the l or0 of one bit is recorded. This recording location could be a magneticcore, flip-flop or ony other one bit device. In summary, the schematicoperation is to record each digit of six bits in a horizontal row a bitat a time, then advance vertically to the next row for the next digit.

The from car detector input is either from some separate device such asa strain gauge on the track or it could be a special extra digit codesuch as all zeros, that is a code pattern block 42, ofred-red-red-red-red-red, that would come from the bit counter 86. Thisinput will cause the record of one vehicle is read out into whateverrecording medium or transmission line is to utilize the information. Forthis purpose, the digit counter lllfi will rest, read-out a digit,advance, read-out the next digit and finally reset after the last digitand stand ready for the next vehicle.

Referring to FIG. 8, marking information is sensed as follows: Color Ralone RT? represents informational 0; the and gate receiving RE puts outan electrical one to indicate this on the line labeled 0. Color G aloneR represents informational "1; the and gate receiving EG puts out anelectrical one on the line labeled 1. Both together RG, i.e. white,serve to switch between bits; the and gate receiving RG puts out anelectrical one on the line labeled T for transfer. Absence of both E (noreflection) serves to switch between digits of characters; the gatereceiving ET; puts out an electrical one on the line labeled Re forreset.

Initially all bit counter fiipmops 122., 126, 130 and so forth are reset(Re) and all memory elements are zero or reset. In this condition awhite or T signal will have no effect. Either a l or a 0 signal will setthe first flip-flop through the or gate. if it is l, the first flipflopset and the second reset will allow it to pass the and gate 132 below tothe record one first bit line 134.

The first fiip-fiop 122 set opens an and gate 12d over second flip-flop126 to allow a T signal to set it. This in turn opens an and gate 128over a further flip-flop 130 and allows either a l or 0 signal to set itand also closes an and gate 132 to the record one first bit line 134. Ifthe second bit is a 1 it passes an and gate 136 to record one second bit138. Successive bits operate lb the successive flip-flops in the sameway until the last flipfiop 114i) is reached or a Re signal is received(FIG. 10).

A Re signal with the last flip-flop 149 still reset through gates 141and or a T signal with the last flip-flop set through gates 143 and 145operates the imperfect digit recorder 142 to substitute the symbol foran imperfect digit for whatever has recorded since the last reset.

A 1 signal at any time during a digit sets an auxiliary flip-flop 144indicated in FIG. 10. When this remains reset as the last regularflip-flop Md is set it indicates an all zero code that marks the end ofone vehicle identification and opens a gate 146 to the to read-out line.If the auxiliary flip-flop 1 and the last regular flip-flop Ml) are set,an Re signal resets all flip-flops. But if the readout operates, itsreturn signal resets all fiip-fiops. The imperfect digit recorder 142also resets all fiip-fiops. Resetting all flip-flops also advances thedigit counter The to advance to the next digit in the memory. A typicalmemory element is shown in FIG. 9.

Another approach to the same logical performance is by use of shiftregisters. A shift register is an assemblage of memory elements soarranged that when a shift signal is applied the entire informationcontent is shifted one step and the element that records the input ismade available for the next input information. in other words the inputinformation is recorded at a single point and then transferred ratherthan the input connection being transferred and the informationremaining at a fixed location.

For this application a full use of the shift principle would involve atwo-dimensional shift; i.e. successive bits would shift down a line toform a digit, then entire digits would shift in a second direction downan assemblage to form a multi-digit identification code.

Other variations of the invention will be apparent to those skilled inthis art. For example, in some applications or circumstances it might bemore effective to pulse the light source at a frequency of a fewthousand cycles and employ an appropriate pulse discrimination functionin the sensing operation. Regular light pulses are considerably moredistinguishable from random ambients than a steady directed beam introublesome milieu.

FIG. 11 shows an alternative form of the optical system shown in Fl 4.Light source 48A with a vertical line filament at the rear focus 5b ofelliptic mirror 52 causes a vertical line of light to concentrate at thefront focus 54, at which limiting slit 2% is located. Field lens 2% concentrates the light emerging from slit 2% in a narrow beam. This beampasses through projection obiective lens 204 which focuses the lightinto a concentrated narrow line on the markings 2% of the vehicle it tobe identified. Lens 2% must have good definition and color correction toform the desired narrow line.

The retro-reflected light from the markings 2h falls on the entiresurface of the lens Light on either side of the narrow source beam fallson dichroic mirror 64, from which one color is transmitted to lightsensitive elements 66 and the other color is reflected to li htsensitive elements Shields 2% prevent stray light from the source fromreaching the light sensitive elements 66 and 68.

High frequency modulation of the light may be produced by vibrating thesides of slit 2% electromagnetically.

Since still other variations of the preferred embodiment of theinvention will occur to those skilled in the art, it is not intended toconfine the invention to the recise form herein shown, but to limit itin terms of the appended claims.

I claim:

1. An identification system adapted to give positive identification ofindividual objects moving sequentially along a predetermined path, saidsystem comprising an interrogating unit located at a fixed positionalong side said path, said interrogating unit including a light sourceand an optical system, said light source emitting a broad spectrum oflight including at least two distinct and distinguishable bands oflight, said optical system directing such light in a narrow orientedbeam intercepting the path of travel of said objects; light reflectingmarkings positioned on said moving objects in position to intercept saidbeam of light, each said marking formed of a plurality of elongatedstrips of retro-reflective material adapted to reflect lightsubstantially along the same axis as the axis of light incident thereon,said strips oriented parallel to the orientation of said light beam andarranged as to be successively illuminated by said beam, the material insaid strips being selected from retro-reflective material havingreflection-absorption characteristics of a plurality of types, saidtypes reflecting variously each of said bands while absorbing the otherof said bands and reflecting a plurality of said bands simultaneously,said strips arranged by type in a predetermined code pattern, which codepattern may include operationally non-reflector strips as well as stripshaving said differing reflection characteristics; a sensing unit locatedat a fixed position alongside said path in close association with saidinterrogating unit and adapted to receive the retro-reflective lightbeam emitted from said interrogating unit and reflected from said lightreflecting markings, said sensing unit including a light mask, a lightsplitting means and a plurality of photo-electric light scnsin means,said light mask having an elongated light passing slit oriented parallelto the orientation of said light beam, and of said coded strips, saidslit having a Width such that only light of a beam width narrowe thatnthe image of any given strip in said light reflecting marking is passedthcrethrough, said light splitt 'ig means comprising at least onedichroic mirror positioned in the path of said reflected beam andadapted to reflect light of one said band and to transmit light of anyother said band to one of said photo-electric light sensing meanspositioned in each path of light emitted from asid light splittingmeans, each said photo-electric light sensing means adapted to convertan incident light input to an electrical output; and data processingmeans operative in respo se to the electrical output or" saidphotoelectric light sens g lllScIlS to convert and transmit such outputin intelligent form.

An identification system as claimed in claim 1 wherein said sensing unitis shielded from light directly emitted from said interrogating unit.

3. An identification system as claimed in claim 1 wherein said beam isdirected at an angle to the path of travel of said moving object, saidangle deviating from the normal.

4. An identification system as claimed in claim 1 wherein a shieldblocking spectral light is provided behind said sensing unit.

5. An identification system as claimed in claim 1 wherein independentmeans are provided to detect the presence of and object in beamintercepting position.

6. An identification system as claimed in claim 1 wherein means areprovided to cause said light to be emitted in pulses.

7. An identification system as claimed in claim 6 wherein means areprovided rendering said sensing unit non-responsive except to saidpulsed li ht when reflected.

8. An identification system adapted to give pcidentiflcation ofindividual railway cars as said cars. move along a track, said systemcomprising an interrogating unit located at a fixed position alongsidesaid track, said interrogating unit including light source and anoptical system, said light source emitting a broad spectrum of lightincluding at leas two distinct and distinguishable bands of light. saidoptical system directing such light in a narrow oriented beamintercepting the path of travel of said cars; a light reflecting markingposition on the side of each of said cars in position to intercept saidbeam of light, each said marking formed of a plurality of elongatedstrips of retroreflecttvc material adapted to reflect light Gilsubstantially along the same axis as the axis of light incident thereon,said strips oriented parallel to the orientation of said light beam andarranged as to be successively illuminated by said beam, the material insaid strips being selected trom retroreflective material havingrcllection absorption characteristics of a plurality of types, saidtypes reflecting variously each of said bands while absorbing the 0 .16!of said bands and reflecting a plurality of said bands simultaneously,said strips arranged by type in a predetermined code pattern, which codepattern may include operationally nonrcflective strips as well as stripshaving the said differing reflection characteristics; a sensing unitlocated at a fixed position alongside said track in close associationwith said interrogating unit and adapted to receive the retro-reflectivelight beam emitted from interrogating unit and reflected from said lightreflecting marking, said sensing unit including a light mask, a light slitting means and a plurality of photo-electric light sensing means,said light mask having an clongated light passing slit oriented parallelto the orientation of said light beam and of said coded strips, saidslit having a width such that only light of a beam width narrower thanthe image of any given strip in said light reflecting marking is passedthercthrough, said light splitting means comprising at least onedichoric mirror positioned in the path of said reflected beam andadapted to reflect light of one said band and to transmit light of anyother said band, one of said photo-electric light sensing meanspositioned in each path of light emitted from said ligi t splittingmeans, each said photo-light sensing means adapted to convert anincident light input to an electrical output; and data processing meansoperative in response to the electrical output of said photoelectriclight sensing means to convert and transmit such output in intelligentform.

9. An identification system adapted to give positive identification or":ndividual railway cars as said cars move along a track, d systemcomprising an interrogating unit located at a fixed position alongsidesaid track, said rrogating unit including a light source and an opticalem, said light source emitting a broad spectrum of light including atleast two distinct and distinguishable colors, sa optical systemdirecting said light in a narrow oriented beam intercepting the path oftravel of said cars; a light reflecting marking position on the side ofeach of said cars in position to intercept said beam of light, each saidrr g formed of a plurality of elongated strips of retro-reflectivematerial adapted to reflect light substantially along the same aais asthe axis of light incident thereon, said strips oriented parallel to theorientation of said light beam and arranged as to be successivelyillumimated by said beam, the material in said strips being selectedfrom retro-reflective material having varying refleeting characteristicsas to reflect both said color simultaneously and to reflect each of saidcolors separately, said strips arranged by type in a predetermined codepattern, which code pattern may include operationally nonreflectivestrips as well as strips having the said differing reflectioncharacteristics; a sensing unit located at a fixed position alongsidesaid track in close association with said interrogating unit and adaptedto receive the retro-reflected light beam emitted from saidinterrogating unit and reflected from said light reflecting markings,said sensing unit including a light mask, a light splitting means and apair of photo-electric light sensing means, said light mask having anelongated light passing slit oriented parallel to the orientation ofsaid light beam and of said coded strips, said slit having a width suchthat only light of a beam width narrower than the image of any givenstrip in said light reflecting marking is passed therethrougli, saidlight splitting means comprising a dichoric mirror positioned in thepath of said reflected beam and adapted to reflect one said color and totransmit the other said color, one of said photoelectric light sensinglilCZlliS positioned to intercept each said color as it emerges fromsaid light splitting means, each said photo-electric light sensing meansadapted to convert an incident light input to an electrical output anddata processing means operative in response to the electrical output ofsaid photoelectric light sensing means to convert and transmit saidoutput in intelligent form.

10. An automatic car identification system comprising a track side carscanning unit and a coded identification marker placed on the side ofeach car, said coded identification marker comprising a predeterminedarray of parallel strips of retro-reflective material arranged accordingto a pie-established code, said strips selected from strips selectivelyand individually reflecting light of at least two separate and distinctcolors, as well as light of at least two said colors simultaneously whenilluminated by a light source including both said colors, said codebeing based on the sequential arrangement of strips having said varyingreflective characteristics; said track side car scanning unit comprisingmeans for illuminating successively the strips in said marker with lightincluding all said colors, means in close association with saidilluminating means for receiving the light retro-reflected from saidmarker, said light receiving means including photo-electric means forseparately detecting each of said colors in said code; means forlimiting the effective retro reflected beam received by said lightreceiving means to a Width less than the image of an individual strip;and means for converting the electrical output of said photoelectricmeans into an intelligent form.

11. An automatic car identification system as claimed in claim 10wherein the said strips are selected from strips reflecting two colorsindividually and from strips reflecting both colors simultaneously;wherein said light receiving means includes means for splitting thereflected light into a separate beam for each said color and aphoto-electric means for detecting each said split beam individually andconverting light incident thereon into an electrical signal; and whereinsaid code is based on the sequential actuation of said photo-electricmeans by light retro-reflected from said marker according to apredetermined pattern involving comparison of electrical output fromeach said photo-electric means according to whether either, neither orboth are actuated.

12. An automatic car identification system as claimed in claim 11wherein separate means are provided for detecting the presence of a carin light intercepting position.

References Qited in the file of this patent UNITED STATES PATENTS2,268,498 Bryce Dec. 30, 1941 2,581,552 OI-Iagan Jan. 8, 1952 2,628,572Legoft Feb. 17, 1953 2,689,338 Singleton Sept. 14, 1954 2,761,122Singleton Aug. 28, 1956 2,916,624 Angel Dec. 8, 1959 2,922,893 Ett Jan.26, 1960 2,981,836 Davis Apr. 25, 1961 FOREIGN PATENTS 800,190 GreatBritain Aug. 20, 1958 857,797 France Sept. 28, 1940

1. AN IDENTIFICATION SYSTEM ADAPTED TO GIVE POSITIVE IDENTIFICATION OFINDIVIDUAL OBJECTS MOVING SEQUENTIALLY ALONG A PREDETERMINED PATH, SAIDSYSTEM COMPRISING AN INTERROGATING UNIT LOCATED AT A FIXED POSITIONALONG SIDE SAID PATH, SAID INTERROGATING UNIT INCLUDING A LIGHT SOURCEAND AN OPTICAL SYSTEM, SAID LIGHT SOURCE EMITTING A BROAD SPECTRUM OFLIGHT INCLUDING AT LEAST TWO DISTINCT AND DISTINGUISHABLE BANDS OFLIGHT, SAID OPTICAL SYSTEM DIRECTING SUCH LIGHT IN A NARROW ORIENTEDBEAM INTERCEPTING THE PATH OF TRAVEL OF SAID OBJECTS; LIGHT REFLECTINGMARKINGS POSITIONED ON SAID MOVING OBJECTS IN POSITION TO INTERCEPT SAIDBEAM OF LIGHT, EACH SAID MARKING FORMED OF A PLURALITY OF ELONGATEDSTRIPS OF RETRO-REFLECTIVE MATERIAL ADAPTED TO REFLECT LIGHTSUBSTANTIALLY ALONG THE SAME AXIS AS THE AXIS OF LIGHT INCIDENT THEREON,SAID STRIPS ORIENTED PARALLEL TO THE ORIENTATION OF SAID LIGHT BEAM ANDARRANGED AS TO BE SUCCESSIVELY ILLUMINATED BY SAID BEAM, THE MATERIAL INSAID STRIPS BEING SELECTED FROM RETRO-REFLECTIVE MATERIAL HAVINGREFLECTION-ABSORPTION CHARACTERISTICS OF A PLURALITY OF TYPES, SAIDTYPES REFLECTING VARIOUSLY EACH OF SAID BANDS WHILE ABSORBING THE OTHEROF SAID BANDS AND REFLECTING A PLURALITY OF SAID BANDS SIMULTANEOUSLY,SAID STRIPS ARRANGED BY TYPE IN A PREDETERMINED CODE PATTERN, WHICH CODEPATTERN MAY INCLUDE OPERATIONALLY NON-REFLECTOR STRIPS AS WELL AS STRIPSHAVING SAID DIFFERING REFLECTION CHARACTERISTICS; A SENSING UNIT LOCATEDAT A FIXED POSITION ALONGSIDE SAID PATH IN CLOSE ASSOCIATION WITH SAIDINTERROGATING UNIT AND ADAPTED TO RECEIVE THE RETRO-REFLECTIVE LIGHTBEAM EMITTED FROM SAID INTERROGATING UNIT AND REFLECTED FROM SAID LIGHTREFLECTING MARKINGS, SAID SENSING UNIT INCLUDING A LIGHT MASK, A LIGHTSPLITTING MEANS AND A PLURALITY OF PHOTO-ELECTRIC LIGHT SENSING MEANS,SAID LIGHT MASK HAVING AN ELONGATED LIGHT PASSING SLIT ORIENTED PARALLELTO THE ORIENTATION OF SAID LIGHT BEAM, AND OF SAID CODED STRIPS, SAIDSLIT HAVING A WIDTH SUCH THAT ONLY LIGHT OF A BEAM WIDTH NARROWER THANTHE IMAGE OF ANY GIVEN STRIP IN SAID LIGHT REFLECTING MARKING IS PASSEDTHERETHROUGH, SAID LIGHT SPLITTING MEANS COMPRISING AT LEAST ONEDICHROIC MIRROR POSITIONED IN THE PATH OF SAID REFLECTED BEAM ANDADAPTED TO REFLECT LIGHT OF ONE SAID BAND AND TO TRANSMIT LIGHT OF ANYOTHER SAID BAND TO ONE OF SAID PHOTO-ELECTRIC LIGHT SENSING MEANSPOSITIONED IN EACH PATH OF LIGHT EMITTED FROM SAID LIGHT SPLITTINGMEANS, EACH SAID PHOTO-ELECTRIC LIGHT SENSING MEANS ADAPTED TO CONVERTAN INCIDENT LIGHT INPUT TO AN ELECTRICAL OUTPUT; AND DATA PROCESSINGMEANS OPERATIVE IN RESPONSE TO THE ELECTRICAL OUTPUT OF SAIDPHOTOELECTRIC LIGHT SENSING MEANS TO CONVERT AND TRANSMIT SUCH OUTPUT ININTELLIGENT FORM.